Lift systems, line brakes, and methods of vertically moving loads

ABSTRACT

A lift system includes an overhead support, a counterweight, a base unit including a brake and secured to a floor, a fly line, and a load line. The fly line connects the counterweight, the overhead support, and the base unit via pulleys. The brake is configured to engage the fly line to limit movement of the counterweight and a load. A manual rope brake includes a housing having a base portion, an upper portion, and a hinge rotatably connecting the upper portion to the base portion. A cam lock is within the housing between pulleys. The cam lock engages a rope when the brake is engaged, and disengages from the rope when the brake is disengaged. A portable lift system includes a container configured to carry pulleys, a base unit, a fly line, and a load line when the lift system is in transport. Related methods are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.14/631,094, filed Feb. 25, 2015, the disclosure of which is herebyincorporated herein in its entirety by this reference.

FIELD

Embodiments of the present disclosure relate generally to liftingsystems and methods, such as portable lifting systems that may betemporarily installed in, for example, a theater.

BACKGROUND

Rigging or lifting systems are used in theaters to raise and lowerobjects on and off stage. For example, scenery backdrops may be raisedand lowered by a system of ropes, cables, pulleys, tracks, weights,motors, etc. For example, a rope or cable may be secured to a motorizedwinch assembly, around one or more pulleys attached to a frame aboveand/or around the stage, and connected to an object to be lifted (e.g.,scenery, curtains, props, an actor, etc.). Some systems may be manuallyoperated, in which ropes are raised and lowered by stage hands, and tiedoff when not being used to raise or lower loads.

Particular attention should be paid to safety of theatrical liftingsystems because a falling load can lead to injuries or loss of life.Safety while lifting humans (e.g., actors) is especially important.During performances, it is sometimes desirable to raise and loweractors, such as to create the illusion of flying. Lifting systems forsuch applications should be easy to operate and be fast enough to createthe desired visual effect when moving the actor.

Some productions are performed at various theaters around the country orthe world. Crew typically pack and ship nearly everything needed for aparticular show, relying on each location to have only the most basicfacilities, such as a stage, overhead supports, lights, curtains, etc.Producers of traveling productions therefore may tend to choose props,costumes, etc., that are lightweight and that can be packed intorelatively smaller space than productions that are not expected totravel. Producers may also choose to modify scripts to avoid the need tocarry some equipment or to avoid the need for facilities or equipmentthat will not be available. For example, if adequate facilities forlifting actors are not expected to be available, a producer may modifyor remove a flying scene to avoid the need lift an actor.

BRIEF SUMMARY

In some embodiments, a lift system includes an overhead support havingat least a first pulley and a second pulley, a counterweight having atleast an upper pulley and a lower pulley, a base unit secured to afloor, a fly line connected to the overhead support and the base unit,and a load line. The base unit includes a brake and at least one pulley.The fly line passes around the upper pulley of the counterweight, aroundthe at least a first pulley of the overhead support, around the at leastone pulley of the base unit, and around the lower pulley of thecounterweight. The load line is connected to the counterweight passingaround the second pulley of the overhead support and connected to aload, such that a change in elevation of the counterweight correspondsto a change in position of the load. The brake is configured to engagethe fly line to limit movement of the counterweight.

A manual line brake includes a housing having a base portion, an upperportion, and a hinge rotatably connecting the upper portion to the baseportion. A first pulley is rotatably secured to the base portion of thehousing. A second pulley is rotatably secured to the upper portion ofthe housing. A cam lock is within the housing between the first pulleyand the second pulley. The cam lock is configured to engage a ropepassing from the first pulley to the second pulley when the upperportion of the housing is in a first position, and the cam lock isconfigured to disengage from the rope when the upper portion of thehousing is in a second position.

A method of vertically moving a load includes routing a fly lineadjacent at least one pulley secured to a counterweight, adjacent atleast one pulley secured to an overhead support, through a base unitcomprising at least one pulley and a manual brake, and adjacent at leastanother pulley secured to the counterweight. The method also includesrouting a load line adjacent at least one pulley, securing the base unitto a floor below the overhead support, applying a force to the base unitto disengage the manual brake, and pulling the fly line to move thecounterweight vertically in a first direction and to move a loadvertically in a second direction substantially opposite the firstdirection. Ends of the fly line are secured to the overhead support andto the base unit, and ends of the load line are secured to thecounterweight and to the load.

A portable lift system includes a plurality of pulleys, a base unitconfigured to be secured to a floor, a fly line, a load line, and acontainer configured to carry the plurality of pulleys, the base unit,the fly line, and the load line when the lift system is in transport.The base unit includes at least one pulley and a brake. The containerincludes a frame defining a plurality of mounting holes configured to besecured to at least two pulleys of the plurality when the portable liftsystem is in use. The container is configured to vertically carry acounterweight when the portable lift system is in use. The brake isconfigured to engage the fly line to limit movement of thecounterweight.

In some embodiments, a method of operating a lift system includesdisengaging a manual brake, pulling the first fly line to move acounterweight vertically in a first direction and move a first loadvertically in a second direction, and engaging the manual brake to limitmovement of the first fly line. The manual brake is configured to limitmovement of a first fly line when the manual brake is engaged when themanual brake and the first fly line are located at a first location. Thesecond direction is substantially opposite the first direction, and thecounterweight comprises a container. The method may further includedisposing the manual brake within the container, transporting thecontainer with the manual brake therein to a second location,configuring the manual brake to limit movement of a second fly line atthe second location when the manual brake is engaged, disengaging themanual brake, pulling the second fly line to move the counterweightvertically in a third direction and move a second load vertically in afourth direction, and engaging the manual brake to limit movement of thesecond fly line. The fourth direction is substantially opposite thethird direction.

A line stopper includes a rigid member defining a tapered cavitytherethrough and a line passing through the tapered cavity. The taperedcavity has a first cross-sectional area at one end thereof and a secondcross-sectional area at an opposite end thereof. The firstcross-sectional area is larger than the second cross-sectional area. Theline has a tapered plug disposed within the line. The tapered plug has ashape corresponding approximately to the shape of the tapered cavity inthe rigid member. The line surrounding the tapered plug has across-sectional area larger than the second cross-sectional area of therigid member.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming what are regarded as embodiments of the presentdisclosure, various features and advantages of embodiments of thedisclosure may be more readily ascertained from the followingdescription of example embodiments when read in conjunction with theaccompanying drawings, in which:

FIGS. 1A and 1B are simplified cross-sectional side views illustratingan embodiment of a lift system according to the present disclosure;

FIGS. 2 through 4 are simplified cross-sectional side views of a baseunit including a line brake of the lift system shown in FIGS. 1A and 1B;

FIG. 5 is a simplified cross-sectional side view of a cam lock andreturn mechanism of the base unit shown in FIGS. 2 through 4;

FIG. 6 is a simplified perspective view of a line stopper in accordancewith an embodiment of the present disclosure;

FIG. 7 is a simplified cross-sectional view of a load line that may beused with the line stopper shown in FIG. 6;

FIG. 8 is a simplified cross-sectional view of a tapered plug that maybe used with the line stopper shown in FIG. 6;

FIGS. 9 through 11 are simplified cross-sectional side viewsillustrating use of the line stopper shown in FIG. 6;

FIG. 12 is a simplified side view of another embodiment of a linestopper; and

FIGS. 13 and 14 are simplified cross-sectional side views of anotherbase unit including a line brake that may be used with the lift systemshown in FIGS. 1A and 1B.

DETAILED DESCRIPTION

The illustrations presented herein are not actual views of anyparticular lift system, but are merely idealized representations thatare employed to describe example embodiments of the present disclosure.Additionally, elements common between figures may retain the samenumerical designation.

As used herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise.

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items.

As used herein, relational terms, such as “first,” “second,” “top,”“bottom,” “upper,” “lower,” “over,” “under,” etc., are used for clarityand convenience in understanding the disclosure and accompanyingdrawings and do not connote or depend on any specific orientation ororder, except where the context clearly indicates otherwise.

As used herein, the term “substantially,” in reference to a givenparameter, property, or condition, means to a degree that one ofordinary skill in the art would understand that the given parameter,property, or condition is met with a small degree of variance, such aswithin acceptable manufacturing tolerances.

As used herein, the term “location” in reference to a lift system orcomponents thereof means a place where a lift system is used orinstalled, encompassing the volume within the operating limits of thelift system as installed. Though some parts of the lift system moveduring use of the lift system, the system itself is considered to be ata location bounded by the outer extent of positions in which componentsof the lift system may be without disconnecting such components of thelift system.

A lift system according to the present disclosure may include anoverhead support, a counterweight, a base unit, a fly line, and a loadline. The overhead support, the counterweight, and the base unit eachinclude pulleys to guide the lines in the system. The base unit may alsoinclude a brake to stop the lines from moving. The fly line is connectedat either end to the overhead support and the base unit, and the flyline passes around an upper pulley of the counterweight, around at leastone pulley of the overhead support, around at least one pulley of thebase unit, and around a lower pulley of the counterweight. The load lineis connected to the counterweight and a load, passing around a pulley ofthe overhead support. In operation, a change in elevation of thecounterweight corresponds to a change in position (typically elevation)of the load. The counterweight may be selected to have approximately thesame mass as the load, such that an operator need not expend excessiveeffort to raise or lower the load.

FIG. 1A illustrates a simplified view of a lift system 100. The systemincludes a load line 102 that may be configured to raise and lower aload 111 (see FIG. 1B). A fly line 104 (which may be referred to in theart as a “purchase line,” “operating line,” or “hand line”) routedaround pulleys 106 a, 106 b, etc. (collectively referred to as pulleys106), and secured to an overhead support 108, is configured to move acounterweight 110 vertically and therefore move the load 111 attached tothe load line 102. As shown in FIG. 1A, one end 105 of the fly line 104is secured to the overhead support 108, and an opposite end 107 of thefly line 104 is secured to a base unit 118. The fly line 104 is routedaround pulleys 106 a, 106 b (which may be secured to a bracket 103 or toa part of the counterweight 110), pulleys 106 c, 106 d (which may besecured to or part of the overhead support 108), pulleys 106 e, 106 f(which may be secured to or part of the base unit 118), and pulley 106 g(which may be secured to or a part of the counterweight 110). Anoperator may pull the fly line 104 one direction or the other (up ordown from the perspective of FIG. 1A) to move the counterweight 110upward or downward.

A portion of the lift system 100 is shown in FIG. 1B. In particular,FIG. 1B illustrates the load line 102, which connects the counterweight110 to the load 111. The fly line 104 and its associated pulleys 106 areomitted from FIG. 1B for clarity. The load line 102, passing over pulley106 h (and optionally one or more additional pulleys 106 i, such as maybe secured to another overhead support 109) moves the load 111 inresponse to movement of the counterweight 110. The lift system 100 mayfurther include a line stopper 113 configured to limit the distance theload line 102 can travel. The line stopper 113 may control the length ofload line 102 between the counterweight 110 and the load 111. The linestopper 113 may be used to attach and detach the load 111 to and fromthe load line 102, and may be used to adjust the position of the load111 with respect to the counterweight 110. In some embodiments, the linestopper 113 may be movable along the length of the load line 102.

The line stopper 113 is shown in more detail in FIG. 6. The line stopper113 may include a rigid member 121 defining a tapered cavity 148 throughwhich the load line 102 passes. The tapered cavity 148 need not have astraight taper. For example, the wall of the tapered cavity 148 may havea conical shape, a parabolic shape, a spline, a flare, a shapecorresponding to a portion of an elliptical trace, or some other shapehaving a varying cross-section. The tapered cavity 148 extends from alarge opening 141 to a small opening 142. The load line 102 may have aportion 115 having a thickness greater than a thickness of the remainderof the load line 102, and may have an exterior shape correspondingapproximately to the shape of the tapered cavity 148. The maximumthickness of the portion 115 of the load line 102 may be greater than awidth of the small opening 142 of the line stopper 113. The portion 115of the load line 102 may include strands of rope woven around a solidobject. For example, FIG. 7 illustrates part of the load line 102 inwhich the portion 115 is woven around a tapered plug 119. The taperedplug 119 is shown alone in FIG. 8. After the portion 115 passes throughthe large opening 141, the portion 115 (including the tapered plug 119)may become wedged in the tapered cavity 148 of the rigid member 121,preventing further movements of the load line 102 in one direction. Theshape of the tapered plug 119 may help distribute pressure from the linestopper 113 to the load line 102, and may prevent premature failure ofthe load line 102.

The tapered plug 119 may be movable within the load line 102, such as byreleasing tension on the load line and sliding the tapered plug 119inside the load line 102. In conventional systems, metallic slugs may becrimped onto wire ropes. However, some types of ropes (e.g., highmodulus polyethylene (HMPE), aramid, liquid crystal polymer, etc.) canbe damaged by crimping and removing metallic slugs. Because the taperedplug 119 disclosed herein need not crimp the load line 102, the taperedplug 119 may be used with such ropes.

The line stopper 113 may be used as a termination or attachment of theload line 102 to the counterweight 110, as shown in FIGS. 9 through 11.As shown in FIG. 9, the load 111 may initially rest on a floor 123, andthe line stopper 113 may be secured to a portion of the load line 102away from the counterweight 110. The counterweight 110 may be held inplace by the fly line 104 and its associated pulleys 106 (not shown inFIGS. 9 through 11; see FIG. 1A). The load line 102 may include a hook125 or other means for securing the load 111 to be lifted. The hook 125may be allowed to lower, which raises the line stopper 113, such asuntil the line stopper 113 contacts the bracket 103. The hook 125 maythen be secured to the load 111, as shown in FIG. 10. With the linestopper 113 in contact with the bracket 103, movement of thecounterweight 110 may cause an equal and opposite movement of the load111. For example, FIG. 11 illustrates that the counterweight 110 hasmoved downward while the load 111 has been raised above the floor 123.

The line stopper 113 may be used a variety of systems in which a movabletermination or midline attachment is desirable. That is, the linestopper 113 may be beneficial even for applications in which there is nocounterweight.

Referring again to FIG. 6, the line stopper 113 may include anattachment point 144 for securing a safety line 117 (see FIG. 1B), whichmay be secured to a wall, the floor 123, the base unit 118 (see FIG.1A), etc. The line stopper 113 may also include a flange 146. The flange146 may be used to assist in installing the line stopper 113 incompression. The flange 146 may also be used to help separate the linestopper 113 from the portion 115 of the load line 102 after the portion115 has become wedged in the tapered cavity 148 (e.g., by tapping theflange 146 with a mallet). The flange 146 may also act as a contactpoint for pressing against the bracket 103 when the line stopper 113 isa termination (see FIGS. 10 and 11).

The line stopper 113 may include a metal, an alloy, a polymer, acomposite, or any other selected material. For example, the line stopper113 may be formed of an aluminum alloy (e.g., aluminum alloy 7075) or ofsteel.

FIG. 12 illustrates another embodiment of a line stopper 113′ that maybe used with the system 100. The line stopper 113′ may include a rigidmember 121′ defining a tapered cavity 148′ through which the load line102 passes. The tapered cavity 148′ extends from a large opening 141′ toa small opening 142′. A pin 150 may pass through sides of the linestopper 113′ for attachment to rigging equipment (e.g., ropes, cables,hooks, etc.). The load line 102 may include a portion 115′ having athickness greater than a thickness of the remainder of the load line102, such that the portion 115′ may become wedged into the taperedcavity 148′. The line stopper 113′ may function in substantially thesame way as the line stopper 113 shown in FIG. 6 and described above.

The overhead supports 108, 109 may be built into or otherwise be a partof a theater structure. For example, stages are typically equipped withhead blocks used to support curtains, hoists, etc. The overhead supports108, 109 may also be or include structural building components, such asroof beams. The overhead supports 108, 109 should be robust enough tosupport the weight of the suspended components of the lift system 100and the weight of the load 111. The overhead supports 108, 109 mayinclude various pulleys, rails, hooks, ropes, and other cables, whichdevices may be independent of the lift system 100 described herein, orwhich may be used to support components of the lift system 100.

The counterweight 110 may include a container 112, such as a polymericbox, to which the pulleys 106 a, 106 b, 106 g may be secured. Polymericboxes are typically used in the art of theatrical productions to storeand transport equipment, props, costumes, etc., from one venue toanother, and may be referred to as “road cases.” A frame 114 may beattached to or within the container 112 to provide additional strengthand anchor points to handle the stresses associated with use as acounterweight 110. For example, the frame 114 may include metal platesto which pulleys 106 a and 106 b, or pulley 106 g may be attached tospread loads applied by the fly line 104 over a larger area of thecontainer 112. The frame 114 may also include beams, rods, angle iron,etc., to provide further support. The frame 114 may include materialssuch as aluminum, steel, or other metals or alloys, as well as any othermaterial having appropriate physical properties, such as plastics orcomposites. The frame 114 is shown as inside the container 112, but allor a portion of the frame 114 may be outside the container 112 inadditional embodiments. The container may include holes through whichpulleys 106 a, 106 b, 106 g may be attached to the frame 114 (e.g., bybolts or other means). The pulleys 106 a, 106 b, 106 g are illustratedon the outside of the container 112, but one or more of the pulleys 106a, 106 b, 106 g may be mounted within the container 112 so long asappropriate holes are provided to route the fly line 104. Mounting oneor more of the pulleys 106 a, 106 b, 106 g within the container 112 maylimit the volume of the container 112 that can be used for storage andtransport of materials, particularly if the pulleys 106 a, 106 b, 106 ghave relatively large diameters. However, interior mounting of thepulleys 106 a, 106 b, 106 g may eliminate the need to connect thepulleys 106 a, 106 b, 106 g to the container 112 or disconnect thepulleys 106 a, 106 b, 106 g from the container 112.

Removable weights 116 may be placed within the container 112 to make themass of the counterweight 110 comparable to the mass of the load 111 tobe lifted. The number or size of the removable weights 116 may varybased on the mass of the load 111, and may be adjusted from time totime. In some embodiments, the removable weights 116 may be in the formof blocks or bags of relatively uniform mass (e.g., sand bags, concretemix, concrete blocks, bricks, containers of water, etc.). The removableweights 116 may include a material that is readily available on locationwhere the lift system 100 is installed, such that the removable weights116 need not be transported with the other components of the lift system100. The container 112 may have a removable cover or lid, such that theremovable weights 116 may be added or removed as needed. By matching themass of the counterweight 110 to the mass of the load 111, a relativelysmall force on the fly line 104 may raise and lower the load 111.

The base unit 118 may include pulleys and a brake, and may betemporarily or permanently secured to the floor. In some embodiments,the base unit 118 may be mechanically secured to the floor or to anobject, such as by bolts. For example, the base unit 118 may be boltedto a board, pallet, or other object, which may in turn be weighted downby sand bags, concrete mix, concrete blocks, bricks, containers ofwater, etc.

FIG. 2 illustrates the base unit 118 in greater detail. The base unit118 may include a stationary member 120 and a movable member 122connected by a hinge 124. The pulley 106 e may be connected to themovable member 122, and the pulley 106 f may be connected to thestationary member 120. The base unit 118 may include a brake, such ascam lock 126 connected to the stationary member 120 of the base unit 118by a pin 128. The cam lock 126 may be configured to allow the fly line104 to travel freely when the base unit 118 is in a first, unlockedposition, as shown in FIG. 2, and to engage the fly line 104 when thebase unit 118 is in a second, locking position, as shown in FIGS. 3 and4.

For example, the cam lock 126 may have an elongated or partiallyelliptical shape (i.e., a shape corresponding in part to the shape of anellipse), such that in the first position, the fly line 104 can passadjacent the cam lock 126 without touching the cam lock 126. When themovable member 122 is in the second position, the fly line 104 touchesthe cam lock 126, which then may rotate about the pin 128 such that thefly line 104 becomes wedged between the cam lock 126 and the stationarymember 120 until the fly line 104 stops moving. In other words, the flyline 104 may become wedged between the cam lock 126 and the stationarymember 120 of the base unit 118, stopping the cam lock 126 and the flyline 104 from further movement. The direction of travel of the fly line104 may determine which direction the cam lock 126 moves to lock the flyline 104. That is, if the fly line 104 travels in the direction of anarrow 130 shown in the FIG. 3, the cam lock 126 may be pushed to theleft. If the fly line 104 travels in the direction of an arrow 132 shownin the FIG. 4, the cam lock 126 may be pushed to the right. In eithercase, forces applied to the fly line 104 by the cam lock 126 and thestationary member 120 of the base unit 118 may limit or prevent furthermovement of the fly line 104 until the cam lock 126 is returned to aneutral position. When the movable member 122 is up, as in FIGS. 3 and4, the cam lock 126 may be free to shift to prevent the fly line 104from moving other than to wedge the cam lock 126 against the stationarymember 120 of the base unit 118. The base unit 118 may be configuredsuch that the movable member 122 is up, allowing the cam lock 126 tolock the fly line 104, except when a downward force is acting on themovable member 122, such as a person stepping on the movable member 122with his or her foot. Thus, the base unit 118 may serve as a safety lockpreventing movement of the fly line 104 when an operator is not pressingon the movable member 122.

In some embodiments, the movable member 122 of the base unit 118 mayinclude a return mechanism 134 to urge the cam lock 126 into a neutralposition when the movable member 122 is moved to the first, unlockedposition. Thus, when the movable member 122 is down, as in FIG. 2, thefly line 104 may travel freely between the pulleys 106 e and 106 fwithout contacting the cam lock 126. For example, the return mechanism134 may include a body having a shape corresponding to an interiorsurface of the cam lock 126. FIG. 5 is a simplified view showing onlythe cam lock 126 and the return mechanism 134. The return mechanism 134may have two points 136 extending downward corresponding to two voids138 (indicated by dashed lines in FIG. 5) within an upper surface of thecam lock 126. There may be a space between the points 136 of the returnmechanism 134 such that the return mechanism 134 can press downwardaround the pin 128 connecting the cam lock 126 to the stationary member120 of the base unit 118. The shape of the return mechanism 134 and thecam lock 126 may be configured such that the return mechanism 134smoothly returns the cam lock 126 to a neutral position when the returnmechanism 134 pushes against the cam lock 126. Portions of the returnmechanism 134 and/or the cam lock 126 may have relatively smoothsurfaces or be coated with a smooth or non-stick material (e.g.,TEFLON®) to promote the movement of the cam lock 126 by the returnmechanism 134.

FIG. 13 illustrates another base unit 118′. The base unit 118′ mayinclude a stationary member 120′ and a movable member 122′ connected bya hinge 124. Pulleys 106 e′ and 106 f may be connected to the stationarymember 120′. A roller 127 may be connected to the movable member 122′such that the roller 127 can slide vertically in a slot 129 in thestationary member 120′. The base unit 118′ may include a brake, such ascam lock 126 as described above. When the movable member 122′ isdepressed, as shown in FIG. 13, the roller 127 may keep the fly line 104out of contact with the cam lock 126. When the movable member 122′ israised, as shown in FIG. 14, the roller may also raise within the slot129, allowing the fly line 104 to contact and engage the cam lock 126.

Referring again to FIG. 1A, in some embodiments, the lift system 100 mayinclude a tensioner 140 to keep the fly line 104 taut. Because themovable member 122 of the base unit 118 may change the length of thepath of the fly line 104, it may be desirable to take up slack in thefly line 104. The tensioner 140 may be, for example, a spring, a weight,etc. The tensioner 140 is shown in FIG. 1A secured to the end 107 of thefly line 104, connecting the fly line 104 to the base unit 118. In suchembodiments, the tensioner 140 may pull the fly line 104 insubstantially the same direction as the fly line 104 is oriented. Inother embodiments, the tensioner 140 may be configured to pull or pushthe fly line 104 in a direction approximately perpendicular to thedirection of the fly line 104.

The base unit 118 may be configured such that the movable member 122 isup (e.g., in the position shown in FIG. 3 or FIG. 4) unless an externalforce is pushing down on the movable member 122. For example, the weightof the container 112 and/or the load 111 (if the weight of the container112 does not precisely match the weight of the load 111), the tension ofthe fly line 104 (e.g., as maintained by the tensioner 140), and/or theforce of a biasing element on the movable member 122 (e.g., a springwithin the base unit 118) may provide an upward force on the movablemember 122. By defaulting to a position in which the fly line 104 maylock, the base unit 118 may provide a measure of safety againstaccidental release of the fly line 104.

Components of the lift system 100 shown in FIGS. 1A and 1B may be packedand transported to other locations, such as to other theaters or venues.For example, the container 112 may be configured to receive some or allof the pulleys 106, the line stopper 113, the safety line 117, the baseunit 118, the return mechanism 134, the fly line 104, and/or the loadline 102. Some pulleys 106 may typically be available on location, sosome of the pulleys (e.g., the pulleys 106 c, 106 d, and 106 h, eachconnected to the overhead support 108) may not be carried within thecontainer 112. The removable weights 116 may be removed from thecontainer 112 before transport to save space and weight of the container112. Typically, removable weights 116 may be available at or near otherlocations where the lift system 100 is to be used, so expensesassociated with transporting removable weights 116 may be avoided.Avoiding excess weight may be particularly desirable for air travel, andomission of the removable weights 116 may keep the container 112 weightwithin limits that make air travel economically feasible. Thus aproduction requiring lift capabilities may be performed at venues wherebuilt-in systems are not available.

The lift system 100 may be installed at a facility by removingcomponents from the container 112, securing the fly line 104 to theoverhead support 108, and routing the fly line 104 adjacent the pulleys106 as described above. An end 107 of the fly line 104 may also besecured to the base unit 118. Some of the pulleys 106 may be secured tothe container 112, and weights may be added to the container 112 tomatch the weight of the load 111 expected to be lifted by the liftsystem 100. The base unit 118 may be secured to a floor below theoverhead support 108 by weighting the base unit 118 down, securing thebase unit 118 to a weighted object, or mechanically securing (e.g.,bolting) the base unit 118 to the floor, or to another structureweighted to the floor. The load line 102, line stopper 113, and safetyline 117 may be installed as shown in FIG. 1B.

Once the lift system 100 is installed, an operator may lift a load 111by applying a force to the base unit 118 to disengage the cam lock 126,and pulling the fly line 104 to move the counterweight 110 verticallyupward or downward. This moves the load 111, typically in the oppositedirection as the direction the counterweight 110 moves.

To make the lift system 100 relatively easier to operate withoutwinches, motors, or other equipment requiring external energy, the massof the counterweight 110 may be selected to be within approximately 10%of the mass of the load 111 to be lifted in some embodiments, such aswithin about 5% or even within about 1% of the mass of the load 111 tobe lifted. That is, the mass of the counterweight may be between about90% and 110% of the mass of the load 111, between about 95% and about105% of the mass of the load 111, or even between about 99% and 101% ofthe mass of the load 111. A counterweight 110 more closely matched tothe load 111 tends to make moving the load 111 with the lift system 100relatively easier and faster.

The pulleys 106 may be selected to be relatively large to decreasefrictional losses in the lift system 100. For example, larger pulleyscause the load line 102 and/or the fly line 104 to form more gradualbends over the sheaves of the pulleys 106, which gradual bends typicallycorrespond with relatively lower friction. Smaller pulleys 106 may alsobe selected, such as to keep the components small enough to fit within aparticular container 112. In some embodiments, the pulleys 106 may havea sheave diameter from about 1 inch (2.54 cm) to about 8 inches (20.3cm). For example, the pulleys 106 may have a sheave diameter from about2 inches (5.08 cm) to about 6 inches (15.2 cm). In some embodiments, thepulleys may have a sheave diameter of about 4 inches (10.2 cm). Some ofthe pulleys 106 may have different sheave diameters from other pulleys.

The lift system 100 may be used to lift a human, such as an actor onstage, or any other object. The lift system 100 may be configured to beoperated without utilities such as electrical power or compressed air,and the operator may be able to safely raise and lower much more weightthan he could lift with conventional systems, and may be able to raiseand lower loads 111 faster than with conventional systems. The cam lock126, which may be configured to lock to fly line 104 except when theoperator presses down on the base unit 118 (e.g., by stepping on thebase unit 118), as well as the line stopper 113, may help preventaccidental slippage of the fly line 104 and dropping the load 111.

Though described in conjunction with a stage and theatrical productions,the lift system 100 and methods described herein may be used in anysituation requiring the ability to safely lift a load 111. For example,the lift system 100 may be used for building maintenance, construction,search-and-rescue operations, recreation, etc. The lift system 100 maybe particularly useful in locations where lifting is needed on occasion,but not often enough to justify a permanently installed lift system. Thelift system may also be beneficial where utilities to operate motors orwinches are not readily available.

Additional non limiting example embodiments of the disclosure aredescribed below.

Embodiment 1

A lift system comprising an overhead support comprising at least a firstpulley and a second pulley, a counterweight comprising at least an upperpulley and a lower pulley, a base unit secured to a floor, a fly lineconnected to the overhead support and the base unit, and a load line.The base unit comprises a brake and at least one pulley. The fly linepasses around the upper pulley of the counterweight, around the at leasta first pulley of the overhead support, around the at least one pulleyof the base unit, and around the lower pulley of the counterweight. Theload line is connected to the counterweight passing around the secondpulley of the overhead support and connected to a load, such that achange in elevation of the counterweight corresponds to a change inposition of the load. The brake is configured to engage the fly line tolimit movement of the counterweight.

Embodiment 2

The lift system of Embodiment 1, wherein the counterweight comprises acontainer configured to carry the base unit, at least one pulley, thefly line, and the load line.

Embodiment 3

The lift system of Embodiment 2, wherein the container comprises a hardpolymeric box and wherein the counterweight further comprises a weightremovable from the hard polymeric box.

Embodiment 4

The lift system of Embodiment 2 or Embodiment 3, wherein the containercomprises a metal frame.

Embodiment 5

The lift system of any of Embodiments 1 through 4, wherein the brakecomprises a cam lock configured to contact the fly line when the brakeis engaged.

Embodiment 6

The lift system of any of Embodiments 1 through 5, wherein the brake isconfigured to disengage when a force is applied to the brake.

Embodiment 7

The lift system of any of Embodiments 1 through 6, wherein the brake isoperable to engage and disengage the fly line by a human operatorwithout additional energy input.

Embodiment 8

The lift system of any of Embodiments 1 through 7, wherein the liftsystem is operable to change an elevation of the load by a humanoperator without additional energy input.

Embodiment 9

The lift system of any of Embodiments 1 through 8, wherein thecounterweight has a mass approximately equal to a mass of the load.

Embodiment 10

The lift system of any of Embodiments 1 through 9, further comprising atensioner configured to maintain the fly line in a taut condition.

Embodiment 11

The lift system of any of Embodiments 1 through 10, wherein the baseunit is temporarily secured to the floor.

Embodiment 12

The lift system of Embodiment 11, wherein the base unit is temporarilysecured to the floor by a weight.

Embodiment 13

The lift system of any of Embodiments 1 through 12, wherein the baseunit is mechanically secured to the floor.

Embodiment 14

The lift system of any of Embodiments 1 through 13, wherein the baseunit comprises a stationary member and a movable member, the movablemember connected to the stationary member by a hinge.

Embodiment 15

The lift system of Embodiment 14, wherein the brake comprises a movablecam connected to the stationary member of the base unit.

Embodiment 16

A manual line brake comprising a housing comprising a stationary member,a movable member, and a hinge rotatably connecting the movable member tothe stationary member. A first pulley is rotatably secured to thestationary member of the housing. A second pulley is rotatably securedto the movable member of the housing. A cam lock is within the housingbetween the first pulley and the second pulley. The cam lock isconfigured to engage a rope passing from the first pulley to the secondpulley when the movable member of the housing is in a first position,and the cam lock is configured to disengage from the rope when themovable member of the housing is in a second position.

Embodiment 17

The manual line brake of Embodiment 16, wherein engagement of the ropeby the cam lock is configured to limit movement of the rope along a pathbetween the first pulley and the second pulley.

Embodiment 18

The manual line brake of Embodiment 16 or Embodiment 17, wherein themovable member of the housing is configured to be in the first positionwhen a tension of the rope is greater than a downward force applied tothe movable member of the housing.

Embodiment 19

The manual line brake of any of Embodiments 16 through 18, whereinmovement of the rope when the movable member of the housing is in thefirst position moves the cam to a locking position.

Embodiment 20

The manual line brake of any of Embodiments 16 through 19, whereinmovement of the movable member of the housing from the first position tothe second position moves the cam lock to a non-locking position.

Embodiment 21

The manual line brake of any of Embodiments 16 through 19, furthercomprising a return mechanism comprising a body having a shapecorresponding at least partially to a shape of a void defined by the camlock.

Embodiment 22

A method of vertically moving a load comprising routing a fly lineadjacent at least one pulley secured to a counterweight, adjacent atleast one pulley secured to an overhead support, through a base unitcomprising at least one pulley and a manual brake, and adjacent at leastanother pulley secured to the counterweight. The method also includesrouting a load line adjacent at least one pulley, securing the base unitto a floor below the overhead support, applying a force to the base unitto disengage the manual brake, and pulling the fly line to move thecounterweight vertically in a first direction and move a load verticallyin a second direction substantially opposite the first direction. Endsof the fly line are secured to the overhead support and to the baseunit, and ends of the load line are secured to the counterweight and tothe load.

Embodiment 23

The method of Embodiment 22, further comprising selecting thecounterweight to have a mass approximately equal to a mass of the load.

Embodiment 24

The method of Embodiment 23, wherein selecting the counterweight to havea mass approximately equal to a mass of the load comprises selecting thecounterweight to have a mass in a range from about 90% of the mass ofthe load to about 110% of the mass of the load.

Embodiment 25

The method of any of Embodiments 22 through 24, wherein securing thebase unit to a floor below the overhead support comprises securing thebase unit to a movable object having a mass greater than a mass of theload.

Embodiment 26

The method of any of Embodiments 22 through 25, further comprisingremoving the force from the base unit to engage the manual brake andlock the fly line to limit movement of the counterweight and the load.

Embodiment 27

The method of any of Embodiments 22 through 26, wherein pulling the flyline to move the counterweight vertically in a first direction and movethe load vertically in a second direction comprises raising a humanabove a horizontal surface.

Embodiment 28

The method of any of Embodiments 22 through 27, wherein pulling the flyline to move the counterweight vertically in a first direction and movethe load vertically in a second direction comprises pulling the fly lineby a human operator without external energy input.

Embodiment 29

A portable lift system comprising a plurality of pulleys, a base unitconfigured to be secured to a floor, a fly line, a load line, and acontainer configured to carry the plurality of pulleys, the base unit,the fly line, and the load line when the lift system is in transport.The base unit comprises at least one pulley and a brake. The containercomprises a frame defining a plurality of mounting holes configured tobe secured to at least two pulleys of the plurality when the portablelift system is in use. The container is configured to vertically carry acounterweight when the portable lift system is in use. The brake isconfigured to engage the fly line to limit vertical movement of thecontainer.

Embodiment 30

The portable lift system of Embodiment 29, further comprising atensioner configured to keep the fly line taut when the portable liftsystem is in use.

Embodiment 31

A method of operating a lift system, comprising disengaging a manualbrake, pulling a first fly line to move a counterweight vertically in afirst direction and move a first load vertically in a second direction,and engaging the manual brake to limit movement of the first fly line.The manual brake is configured to limit movement of a first fly linewhen the manual brake is engaged when the manual brake and the first flyline are located at a first location. The second direction issubstantially opposite the first direction, and the counterweightcomprises a container. The method may further include disposing themanual brake within the container, transporting the container with themanual brake therein to a second location, configuring the manual braketo limit movement of a second fly line at the second location when themanual brake is engaged, disengaging the manual brake, pulling thesecond fly line to move the counterweight vertically in a thirddirection and move a second load vertically in a fourth direction, andengaging the manual brake to limit movement of the second fly line. Thefourth direction is substantially opposite the third direction.

Embodiment 32

The method of Embodiment 31, wherein the second fly line comprises thefirst fly line, and further comprising disposing the first fly linewithin the container before transporting the container to the secondlocation.

Embodiment 33

A line stopper comprising a rigid member defining a tapered cavitytherethrough and a line passing through the tapered cavity. The taperedcavity has a first cross-sectional area at one end thereof and a secondcross-sectional area at an opposite end thereof. The firstcross-sectional area is larger than the second cross-sectional area. Theline comprises a tapered plug disposed within the line. The tapered plughas a shape corresponding approximately to the shape of the taperedcavity in the rigid member. The line surrounding the tapered plug has across-sectional area larger than the second cross-sectional area of therigid member.

While the present invention has been described herein with respect tocertain illustrated embodiments, those of ordinary skill in the art willrecognize and appreciate that it is not so limited. Rather, manyadditions, deletions, and modifications to the illustrated embodimentsmay be made without departing from the scope of the invention ashereinafter claimed, including legal equivalents thereof. In addition,features from one embodiment may be combined with features of anotherembodiment while still being encompassed within the scope of theinvention as contemplated by the inventors. Further, embodiments of thedisclosure have utility with different and various lift types andconfigurations.

1. A line brake, comprising: a housing comprising a stationary member, amovable member, and a hinge rotatably connecting the movable member tothe stationary member; a first pulley rotatably secured to the housing;a second pulley rotatably secured to the housing; a cam lock within thehousing between the first pulley and the second pulley; wherein the camlock is configured to engage a line passing from the first pulley to thesecond pulley when the movable member of the housing is in a firstposition, and wherein the cam lock is configured to disengage from theline when the movable member of the housing is in a second position. 2.The line brake of claim 1, wherein engagement of the line by the camlock is configured to limit movement of the line along a path betweenthe first pulley and the second pulley.
 3. The line brake of claim 1,wherein the movable member of the housing is configured to be in thefirst position when a tension of the line is greater than a downwardforce applied to the movable member of the housing.
 4. The line brake ofclaim 1, wherein movement of the line when the movable member of thehousing is in the first position moves the cam lock to a lockingposition.
 5. The line brake of claim 1, wherein movement of the movablemember of the housing from the first position to the second positionmoves the cam lock to a non-locking position.
 6. The line brake of claim1, further comprising a return mechanism comprising a body having ashape corresponding at least partially to a shape of a void defined bythe cam lock.
 7. A line stopper, comprising: a rigid member defining atapered cavity therethrough, the tapered cavity having a firstcross-sectional area at one end thereof and a second cross-sectionalarea at an opposite end thereof; wherein the first cross-sectional areais larger than the second cross-sectional area; and a line passingthrough the tapered cavity, wherein the line comprises a tapered plugdisposed within the line, the tapered plug having a shape correspondingapproximately to the shape of the tapered cavity in the rigid member,wherein the line surrounding the tapered plug has a cross-sectional arealarger than the second cross-sectional area of the rigid member.
 8. Theline stopper of claim 7, wherein the tapered cavity has a conical shape.9. The line stopper of claim 7, wherein the tapered plug is movablewithin the line.
 10. The line stopper of claim 7, wherein the rigidmember further comprises an attachment point configured for securing asafety line.
 11. The line stopper of claim 7, wherein the rigid memberfurther comprises a flange.
 12. The line stopper of claim 7, wherein therigid member defines at least one opening, and wherein a pin passesthrough the at least one opening.
 13. The line brake of claim 1, furthercomprising a tensioner connected to the line passing from the firstpulley to the second pulley.
 14. The line brake of claim 1, wherein thefirst pulley is rotatably secured to the stationary member of thehousing.
 15. The line brake of claim 1, wherein the second pulley isrotatably secured to the movable member of the housing.
 16. The linebrake of claim 1, further comprising a roller connected to the movablemember and configured to slide within a slot defined by the stationarymember.
 17. The line brake of claim 16, wherein the roller is configuredto slide vertically within the slot defined by the stationary member.18. The line brake of claim 1, the cam lock comprises a body having ashape corresponding in part to a shape of an ellipse.
 19. The line brakeof claim 1, wherein the cam lock comprises a non-stick material.
 20. Amethod of controlling a line using the line brake of claim 1, the methodcomprising: moving the movable member of the housing from the firstposition to the second position to disengage the line from the cam lock;and moving the movable member of the housing from the second position tothe first position to engage the line with the cam lock.